XPS studies of Cu incorporation in arsenic chalcogenides

Addition of rather large amounts of Cu in a-As 2 S 3 and a-As 2 Se 3 , induces suppression of the normally observed photodarkening. We have used X-ray photoelectron spectroscopy (XPS) to examine the effects on the electronic structure of the incorporation of increasing amounts of Cu atoms into the a-As 2 S 3 and a-As 2 Se 3 lattices. We show that initially the addition of Cu affects the environment of the elements in the amorphous chalcogenide glasses, without at the same time suppressing the photodarkening. On the other hand, as more Cu atoms are introduced in the network, Cu aggregates form; the initial chalcogenide electronic structure tends to be restored; and the photodarkening is suppressed.